[Coco] Kicking the Z-80 butts...

[CoCo Demus]

I'd be happy with a new VDG that supports 80 column and runs in 2Mhz. Adds
a static ram mmu to the coco1/2 and you can run OS-9 Level 2 :)

New graphics modes will be completely moot. Take the wordpak2+ I did, it
has 512x212x16 colors or 256x212x19268 colours!, but developing for it is
another story. It has also sprites, hardware scroll, palletes, etc.




On Tue, Apr 28, 2015 at 4:27 PM, John W. Linville <linville at tuxdriver.com>
wrote:

> On Tue, Apr 28, 2015 at 02:20:41PM -0500, Zippster wrote:
> > Well, it is late ‘70s technology.  Earlier that decade the first
> microprocessors were introduced.
> > I guess the 6847’s major weak point is probably the terribly limited 32
> column text display.
> > Other VDGs of the time were pretty low-resolution as well.  But you have
> to remember there
> > wasn’t much resolution available on the display devices either, even if
> you would have had the silicon for it.
>
> IMHO, the only real problem with the 6847 is the available colors.
> Even the individual colors aren't terrible, but the inflexible
> combinations seem to have been chosen by a colorblind sadist...
> Only being able to have green or white (depending on color set chosen)
> for the background color is also...painful.
>
> The 32-character line width in text mode isn't great, but it is a lot
> better than the VIC-20's 22×23 text layout.  And at least with a power
> of 2 for the line width, you don't have to do the arithmetic gymnastics
> required by the Apple II when computing a character's offset in memory!
>
> Overall the resolutions for the 6847 aren't too bad given the time
> it was released.  The fact that it was "off the shelf" should have
> made it very attractive for a variety of uses.  In fact, I know of at
> least one industrial "over computer" that shows-up on eBay from time
> to time that used it.  If the color palette had been more flexible
> then I'll bet it would have been much more highly regarded...
>
>
> > Video is just a massive amount of data once you start to move past
> 300x200 or so and just a few colors.
> > Even the 6809 will start to choke pretty quickly heading in that
> direction.
>
> Which is why the coco3 probably should have had a blitter...
>
> > Although it is a pretty incredible 8-bit CPU with an interesting story
> behind it.
> > It should have been more popular.
>
> How popular were Defender and Robotron? :-)
>
> >
> > - Ed
> >
> >
> > > On Apr 28, 2015, at 1:28 PM, Gustavo Ranaur Schoenaker <
> ranaur at ranaur.net> wrote:
> > >
> > > Really amazing.
> > >
> > > The more I know the 6809 the more I think the problem with the chip
> was no
> > > t the processos, but the 6847. Maybe it was the reason Tandy made the
> GIME
> > > chip on CoCo 3. Video is really the upper limit of the plataform. At
> those
> > > times the video chip make a huge difference.
> > >
> > > Nice job Luis!
> > >
> >
> >
> > --
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>
> --
> John W. Linville                Someday the world will need a hero, and you
> linville at tuxdriver.com                  might be all we have.  Be ready.
>
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